Release process

Pre-release

Confirm CSDMS BMI variable names with Eric Hutton (currently pending for mantle__mass-per-volume_density, infill_material__mass-per-volume_density, planet_surface__gravitational_acceleration). If names change, update gflex/bmi.py, tests/test_bmi.py, docs/api.rst, and CHANGES.md.
Verify CI is green on master before starting.
Bump version in gflex/_version.py:
```
__version__ = "2.0.0"
```
(docs/conf.py and pyproject.toml both pull from this file dynamically.)
Check CHANGES.md — the top entry must be ## [X.Y.Z] — YYYY-MM-DD with no [Unreleased] header above it.
Run the test suite — all tests must pass:
```
python -m pytest
```

Build the docs — zero warnings required:

python -m sphinx docs docs/_build/html -q

Commit the version bump (one commit, e.g. release: bump version to 2.0.0).

Push to GitHub (origin/master).
Wait for CI (test.yml and build-check.yml) to go green.
Create a GitHub Release with tag v2.0.0 (target: master).
- Title: gFlex 2.0.0
- Body: paste the [2.0.0] section from CHANGES.md
- Publishing the release triggers publish.yml automatically.
Approve the PyPI deployment — the pypi environment requires manual approval in the GitHub Actions UI before the package is uploaded.
Verify on PyPI: pip install gflex==2.0.0

Add ## [Unreleased] at the top of CHANGES.md for future patch releases.
Zenodo — a new version record is created automatically via the GitHub integration. Once it appears, update the version-specific DOI in docs/references.rst (currently uses the concept DOI as placeholder).
GRASS GIS — proceed with the r.flexure / v.flexure update (issue #55; branches update/r.flexure and update/v.flexure in ~/models/grass-addons-gflex).
Landlab — PR landlab/landlab#2420 is unblocked once gflex>=2.0.0 is on PyPI. Close issue #73 once that PR merges.